The Jamaica Bay estuary is located on the western end of Long Island, New York (fig. 1), and most of the bay is part of the Jamaica Bay Unit of Gateway National Recreation Area. Historically the bay was known for an abundance and diversity of shellfish. In addition, with extensive marsh islands, tidal creeks, mudflats, and brackish water, the bay has served as an important nursery and feeding ground for many species of birds and fish. However, over time the Jamaica Bay ecosystem has been altered. Urban development has caused widespread changes in the quantity and quality of bay waters and much of the bay shoreline has been hardened and modified. The natural flow of water and sediment into the bay has been affected by channel dredging, stormwater runoff diversion, sewage treatment plant operations, and causeway construction. In addition, the Rockaway Inlet, on the bay’s southern shore, has migrated to the west over many years and has constricted flow into the bay. The bay also has experienced the conversion of more than 60% of the vegetated salt-marsh islands to intertidal and subtidal mudflats. Between 1951 and 2008, 647.5 hectares (1,600 ac) of salt marsh were lost; the current rate of loss is 7.7 hectares (19 ac) per year.